CHICAGO (CBS) — Cook County prosecutors plan to seek a grand jury indictment against 29-year-old Bernard Kersh, the man charged with aggravated battery after police say he threatened and spit in the eye of an officer who body-slammed him on Thanksgiving.

Kersh is charged with aggravated battery and resisting arrest, and was in court on Thursday for what was scheduled to be a preliminary hearing on his case. Instead, prosecutors said they will take his case to a grand jury to decide if he will be formally indicted.

Police have said officers stopped Kersh for drinking alcohol at a bus stop at 79th and Cottage Grove on Thanksgiving, and were writing him a ticket, when he licked an officer’s face, threatened him, and spat in his eye.

Bernard Kersh is charged with aggravated battery and resisting arrest. Police say he spat on and threatened an officer who had stopped him for drinking in public. An officer was caught on video slamming Kersh to the pavement. (Credit: Chicago Police)

Cell phone video of the incident shows the officer lift Kersh off his feet and slam him to the ground. Kersh’s head slams against the curb, and he doesn’t move for the rest of the video.

Police described the maneuver as an “emergency takedown,” but Kersh’s attorneys have called it “a brutal and vicious attack.”

Kersh’s mother, Keshia Johnson, attended his court hearing on Thursday, and she said he’s still suffering severe headaches a week after he was slammed to the pavement.

“I would like for him to see a doctor to make sure he’s okay, because I don’t really know that,” she said.

Kersh is being held in Cook County Jail. His bond was set at $5,000, but his family has said he won’t be released on bail because he’s also being held on a parole violation.

Johnson said she would like her son released so he can get medical and mental health treatment.

The officer who slammed Kersh to the ground has been stripped of his police powers, as has a second officer involved in the incident.

The Chicago Fraternal Order of Police, the union representing rank-and-file officers, has said the officer was in danger, and had to take action.

“This officer was not spit on. He was spit in his mouth and in his eye. I haven’t heard anybody ask about whether he transmitted possibly any disease to this officer, what the situation was that. It’s a felony attack. He engaged in a takedown,” FOP second vice president Martin Preib said.

Preib said the police force is not getting enough support from the public, and is being handcuffed, making it impossible to do their jobs.

Kersh is due back in court on Jan. 15.